是否可以在运行时替换方法? [英] Is it possible to replace a method at runtime?

问题描述

我想创建一个能够在运行时覆盖方法的插件系统.

I want to make a plugin system with the capability to override a method at runtime.

有些答案说了函数指针，但是定义的函数或类呢?

Some answers say function pointers, but how about a defined function or class?

赞:

class foo
{
  public:
    bar(int foobar);
}

是否有办法获取函数指针或替换它?

Is there a way to get function pointer for that, or replace it?

顺便说一句，钩子不被认为是答案，因为它是特定于平台的并且非常危险.

BTW, hooking is not considered an answer because it's very platform specific and dangerous.

推荐答案

运行时功能替换"可以通过以下几种技术之一来实现:

Runtime function "replacement" can be achieved with one of several techniques:

1. 多态
2. 标准库工具，例如 std::function
3. 第三方库或特定于平台的技术来翻译或调度函数调用.

1. Polymorphism
2. Standard library facilities such as std::function
3. Third party libraries or platform specific techniques to translate or dispatch function calls.

哪种选择更好，很大程度上取决于预期的用途和目标环境.例如;插件系统可以很好地利用多态性(通过适当的工厂，甚至可能与模板方法模式)，而内部函数路由可以使用std::function.

On which option is better is highly dependent on the intended use and target environments. For example; plugin systems could well make use of polymorphism (with the appropriate factories and possibly even combined with the template method pattern) whilst internal function routing could use std::function.

这些技术并不会真正替换"任何功能，而是可以在运行时进行设置以根据需要路由功能调用.

These techniques wouldn't really "replace" any of the functions, but rather can be set up at runtime to route the function call as required.

注意我专注于问题的C ++方面(被标记为C和C ++，但示例代码为C ++).

Note I've focused on the C++ aspects of the question (it was tagged C and C++ but the sample code is C++).

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